#include <iostream>
#include <vector>

using std::cout;
using std::endl;
using std::vector;

int main()
{
    vector<int> v{1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
    for (auto it = v.begin(); it != v.end(); it++)
    {
        *it *= 2;
        cout << *it << endl;
    }
}